The role of sciurids and murids in the dispersal of truffle-forming ectomycorrhizal fungi in the Interior Cedar-Hemlock biogeoclimatic zone

Ectomycorrhizal fungi form an integral tripartite relationship with trees and rodents whereby the fungi provide nutritional benefits for the trees, the trees provide carbohydrate for the fungi, and the rodents feed on the fruit bodies produced by the fungi and then disperse the fungal spores in their feces. When forests are harvested, new ectomycorrhizae must form. It has been assumed that dispersal beyond the root zone of surviving trees happens by way of animals dispersing the spores in their feces, but the importance of particular animal taxa to fungal spore dispersal into disturbed areas in the Interior Cedar Hemlock Biogeoclimatic zone of British Columbia has not previously been investigated. This study observed the occurrence and prevalence of hypogeous fruit bodies (truffles) of ectomycorrhizal fungi, and fungal spores in the feces of a range of rodent species. Truffles were excavated and sciurids (squirrels, chipmunks) and murids (mice, voles) were trapped on sites in a 7 to 102-year chronosequence, as well as unharvested sites adjacent to 7- and 25-year-old sites. The average truffle species richness in soil did not change significantly over the chronosequence. Rhizopogon species were present at all sites and treatments. Deer mice (Peromyscus maniculatus) and yellow-pine chipmunks (Tamias amoenus) were the most commonly trapped rodents across all site ages and were also the most likely to move between harvested and unharvested areas. Red-backed voles (Clethrionomys gapperi), red squirrels (Tamiasciurus hudsonicus), and flying squirrels (Glaucomys sabrinus) were also studied, but were trapped in much lower numbers and rarely, if ever, were detected moving between harvested and adjacent mature sites. However, all animal taxa studied carried fungal spores in their feces. Spores of Rhizopogon spp. and Hysterangium separabile were the most frequently consumed by all the animals studied. Because deer mice and chipmunks were the most likely to move between mature and harvested sites and they frequently carried fungal spores in their feces, they are likely the most important mammals for dispersal of ectomycorrhizal fungal spores in this area. This study highlights the importance of small mammal conservation when forest management is considered.Arts and Sciences, Irving K. Barber School of (Okanagan)Biology, Department of (Okanagan)Graduat